The invention relates to such a shunter with which forces can be exerted on the bow and or the stern of a ship in a direction perpendicular to the longitudinal direction of the ship, so that the longitudinal axis of the ship can be brought into a desired position such as is especially desirable when entering or passing though a relatively narrow passage, which shunter has a stern of substantially U-form, and is characterized in that on the innerside of the U-form at least one suction head is present which can attache itself to the ship to be manoeuvered.
Shunters with a U-like bow are known for instance from the U.S. Pat. No. 4,169,423 and the French Pat. No. 745.955. In these patents the use of suction head is not described. The coupling between the shunter and the ship takes place by means of cables and fenders.
The use of suction heads on tugboats is for instance known from the British Pat. No. 1.348.652 and the French Pat. No. 1.580.863. The suction heads according to these patents however are not present in a U-like part of the tugboat but on the deck thereof. They attach to the sides of the hull of the ship; the tugboat therefore has a position alongside the ship to be drawn. For narrow passages this is, as has been set out above, this is totally not acceptable.
The use of a suction head in a U-form prow or bow of a shunter according to the invention is very advantageous with respect to the well known devices because the coupling between the shunter and the ship takes place exactly there where also the directional forces of the shunter are exerted. Moreover cables are superfluous thereby making the coupling action less labor-intensive and moreover expensive cables can be saved. Furthermore a perfect adaptation can be achieved to the form of the hull of the ship to be directed, ship and shunter forming practically one unit.
A shunter according to the invention preferably also has means such as hydraulically operating adjustment cylinders, to adjust the position of the suction head so that a perfect adaptation to the form of the prow of the ship to be directed can be achieved.
It is furthermore very advantageous to use in a shunter according to the invention a so-called schottel-propulsion, which preferably is rotatable.
Also in off-shore operations such as the unloading of the freight of a sea-going ship into barges for inland transportation with the use of a pontoon crane the problem exists that the position of the sea-going ship, the pontoon crane and the barges with respect to each other must be fixed as far as possible. Especially when there is a certain swell this is hard to be realised in practice. To solve this problem so-called swell compensators have been proposed; these however are expensive and complicated and they do not work in the end really satisfactorily.
Also for these purposes the use of a shunter according to the invention brings about a considerable improvement and simplification.
According to a preferred embodiment of a shunter made according to the invention the shunter has a vacuum source and at least one suction head with suction elements closed by a elastic sealing rim and the latter are in connection with the vacuum source.
According to a further preferred embodiment a shunter according to the invention has a suction head which is subdivided into a number of sections with vacuum elements whereby the position of each section is separately adjustable.
With a shunter according to the invention it is possible to exert very large forces so that a good connection is achievable under all circumstances.
With the embodiment where the suction head is subdivided in separately adjustable and displaceable sections it is possible to couple to arbitrarely curved surfaces.